Amp gauge fluctuates at any RPM

[slantsixdan]

round back
you can identify a standard pre 71?? mopar alternator by its round case back

All pre-'72 Chrysler-built alternators are roundbacks. All pre-'69 Chrysler-built alternators are "single-field" items (one brush is grounded to the housing; the other one has this alternator's one and only "FLD" field terminal, which gets a wire from the regulator's own "FLD" terminal).

Most '69 Chrysler-built alternators—again, all roundbacks—are just like the '60-'68 items, but the one for the '69 Imperial is a one-year-only item configured to use a virtually extinct 3-pin electronic regulator.

The '70-'71 Chrysler-built alternators are still roundbacks, but are "2-field" units for use with the 2-pin, triangular-plug electronic regulator.

The '72-up Chrysler-built alternators are all squarebacks, and all 2-field items.

A 2-field alternator can be installed in a pre-'70 car (pre-'73ish truck) by grounding one of the alternator's two "FLD" terminals—doesn't matter which one.

"Type P" and "Type N" terminology…maybe somewhere, but not that I've ever seen in any of the Chrysler or other-source info about these alternators.

 

[Gilad Avital]

Was the problem fixed?
I have the same issue on my 75 Valiant custom.
My parking lights are flickering too....

 

[Mattax]

Was the problem fixed?
I have the same issue on my 75 Valiant custom.
My parking lights are flickering too....

Hello Gilad,
You are best off starting a new thread. Especially in this case because your car is different and this thread has gone all over the place,
Tell us under what conditions you see are observing flickering.
A photo or two of the engine compartment may help as well. The things that can be helpful seeing include the alternator, the voltage regulator and the related wiring connectors, especially at the firewall. Also any modifications or fixes that have been done to it.

Your '75 was wired a little differently than the preceding years, and a lot different than the following model year.

 

[Swinger 340]

no

I agree it's normal with the blinkers flashing. My 69' been doing it for over 40 years. My issue is the speedometer starts at 12 mph and as it increase with speed, it fluctuates at speed. I think there is an adjustment in the back of the panel, for the starting point but the fluctuations, has me stumped.

 

[Dana67Dart]

The speedometer has 2 moving parts that fit inside of each other.

The one is attached to the cable and the other is attached to the needle. Neither have any physical contact with the other (There are others for the odometer, but not relevant here)

When the one that is attached to the cable spins, the magnet in it causes the one attached to the needle to rotate against the internal spring that keeps the needle at 0.

There are small plastic bushings that keep the two parts inline and separated. When the bushings fail the alignment gets off and the one attached to the cable momentarily touches the one attached to the needle.

This monetary contact causes the needle to jump.

You may even be able to hear a faint tick tock tick.

The only fix is to remove the cluster and have the speedo head repaired.

( Another cause COULD be a dry speedo cable that sticks till there is enough force to release it and then the speedo needle rotates faster for a moment till the cable starts to bind again.)


As for a 0 adjustment, there is one but it is internal in the speedo head

 

[Dana67Dart]

Is the bend in the part and the spring steel in the correct location?

 

[Dave999]

did some digging

N- Type
P -Type

looks like they are descriptive terms coined by a fella called Edgar J Beyn who used to write automotive books and books about marine engines in the 1980s...

so chrysler would not have used those terms

i have polluted the board with Marine engine slang...apologies....

Dave

 

[67Dart273]

did some digging

N- Type
P -Type

looks like they are descriptive terms coined by a fella called Edgar J Beyn who used to write automotive books and books about marine engines in the 1980s...

so chrysler would not have used those terms

i have polluted the board with Marine engine slang...apologies....

Dave

We know you meant well, back in the "generator" days, there was "circuit A" and "circuit B". I can never remember which was which without looking them up. They are the same exact idea. That is, some VR are powered from the generator armature, and control the field by sending power to the grounded field. Others work by controlling the grounding on one end of the field, just like the 70/ later VR in Mopar alternators.

(Looked it up) Type A is like 70/ later, VR controls ground leg. Typ B, the VR sends power to a grounded field. One big problem is, Chrysler/ Autolite/ Prestolite systems USED BOTH.

How to tell if A or B generator ci... - Yesterday's Tractors

Is there any way to tell if a generator has an A or B circuitry without tearing it apart to see if the brushes are internally or externally grounded?

www.yesterdaystractors.com